yesb it is
That is the negative portion of a movement. Lowering the weight during a bench press
A concentric movement would be flexing the elbow and curling a dumbbell towards the shoulder, an eccentric contraction would be the opposite movement ie bringing the dumbbell back down towards the thigh.
Eccentric contraction (isotonic)
The correct phase order of the stretch-shortening cycle is eccentric contraction, amortization phase, and concentric contraction. This sequence allows for energy storage during the eccentric phase, a brief pause to transition from lengthening to shortening, and then rapid muscle shortening in the concentric phase for powerful movement.
Example: If you're sitting normally in a chair when your quadriceps contract, your lower leg will be extended, so that it's straight. If you're standing, your leg will go from being bent to being straight.
The different types of contraction in sport is; Concentric Eccentric you also have to include; joint action e.g. Extension / flexion the agonist / agonistic muscle pairs e.g. hamstrings, quadriceps, biceps, triceps ect. & the joint itself e.g. knee, elbow, shoulder,
A sit up is an eccentric muscle contraction.
An eccentric contraction is one that causes a muscle to lengthen.
The eccentric muscle contraction is most likely to cause discomfort in q5.
There are 3 types of muscle contraction in the leg extention and they are Concentric, Isometric, and Eccentric contractions.
During the eccentric contraction phase, cellular activity involves lengthening the muscle fibers while generating force. This phase creates tension in the muscle as it elongates, allowing for controlled movement and resistance against external forces. Additionally, cellular processes such as protein breakdown and remodeling contribute to muscle adaptation and strength gains.
The importance of motor unit stimulation during an eccentric isotonic contraction is to try and keep the unit as stable as possible. Otherwise, the unit may go haywire.